Primitive Archer
Main Discussion Area => Bows => Topic started by: sleek on September 16, 2017, 05:52:36 pm
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My recurves when I bend them keep cracking on the belly side. I use dry heat and bend it around a caul. I have rounded the edged and even chased a belly ring. I am trying to get 90 degree hooks on it. I have left them thick and made them thin hopung for a dufference. I need help.
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What kind of wood?
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Sorry, its osage.
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Try localized steam using only slight hand pressure .let it sit overnight on the caul and then lock it in with dry heat
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I think if u want a 90 deg bend and you are having this much problem boil them
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Get a wall paper steamer sleek. Works great for bending recurves. I got a used one off the big auction site for around $25 shipped.
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Steam for sharp curves. I've never had recurves crack when steaming osage.
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Well I went with a big pot and boiled. You gadda be fast. But i got one tip bent. Boiling the other now.
How does a wallpaper steamer work?
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Anyone had experience with putting something on top of the belly to help prevent it from lifting splinters? (am curious too)
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Well I went with a big pot and boiled. You gadda be fast. But i got one tip bent. Boiling the other now.
How does a wallpaper steamer work?
It's a plastic water tank with a heating element. The steam comes out of a hose. I steamed for 25 minutes before bending it. This was a temporary set up. I'm going to use a steel pipe next time. Danznbar has been using one to steam recurves for a while now. I got the idea from him.
(https://i.imgur.com/qsECNzY.jpg)
(https://i.imgur.com/CL3mFpA.jpg)
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leaving them thick may be counter productive, it's just increasing the tension on the belly.
The strip of thin steel (old tin can etc) over the belly during the bend may help.
Del
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Before I steam, I clamp a thin piece of metal (old bandsaw blade works well) onto the belly with a small C clamp. It stays loose at the tip end. Then, as soon as it comes out of the steam the tip end goes into the caul, which secures the metal strip against the belly, and I bend and clamp.
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OO, if you shorten the hose and leave a good vent hole in the PVC it will work better. I cut my hose down to two feet. You need a good steam flow to keep the heat up. I just loosely stuff rags in the gaps. The hose clamps are a little to much I think. A metal pipe might absorb to much heat. To double check I stick a cooking thermometer into the steam box. It should be 210-211 degrees.
PS at least at sea level, will be lower for you mountain men ;D
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Rub it down with some canola oil. A few minutes of constant movement heat with the heat gun, and it'll be a noodle.
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I do the same as DC, 6" pvc pipe with a garment steamer from Wal-Mart. Works great. I shortened the hose like mentioned, and my pipe is long enough to do one limb. I've been meaning to make a shorter pipe with 2" holes on either end and use it for localized bending.
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This may be just a perceived bias and I accept that I can be proven wrong, but when I am bending something with dry heat, I sand the belly several times throughout as I go. It seems to keep these tears from happening. Or so I would argue.
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interesting point about temp and altitude!if I remember correctly,2 degrees f is lost for every 1000' of rise.
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Denver is about 205f I think.
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For the really sharp bends soak the staves end in water for 3 days or so. Then boil it. Thin steel straps are useful too IF you work out your jigs so it doesn't take more time.
It may take a little longer with the soaking time but for the tightest of tight bends there is no other way ;) and of course green wood with the sap up makes a lot of difference if possible.
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http://www.core77.com/posts/35838/A-Better-Way-to-Steam-Wood-for-Bending-Use-a-Plastic-Bag